Recording instrument.



W. H. PRATT. RECORDING INSTRUMENT. APPLICATION TILED AUG. 10, 1907.

920,084}, Patented Apr. 27, 1909.

2 SHEETS-SHEET 1. F12. I

Witnesses: Inventor: M m WiHiam H. Pratt,

Wyn. PRATT. RECORDING INSTRUMENT. APPLICATION FILED AUG. 10, 1907.

Patented Apr. 27, 1909.

2 SHBET8SHEET 2.

Fig. 5.

itnesses:

UNITED sirarns PATENTS omuon.

WILLIAM 1:1. PRATT, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

. A CORPORATION OF NEW YORK.

RECORDING INSTRUMENT.

Specification of Letters Patent.

Patented April 27, 1909.

Original application filed April 7, 1903, Serial No. 151,459. Divided and this application filed. August 10, 1907. i Serial No. 323,025.

value of some variable quantity cause a record to be made upon a surface having a progressive movement, the speed with which the surface moves being usually some function of the time.

The object of my invention is to improve.

the construction of instruments of this character and my, 1nvent10n consists in certain 1 novel features of arrangement, construction and combination which will be definitely pointed out in the claims annexed to and orming a part of. this specification.

For abetter understanding of my invention reference may be had to the accompanying drawings in which I have illustrated one embodiment of my invention.

Figure 1 is an end elevatlon of the instrument setwith the axis of the moving element horizontal insteadof vertical, as it should be when the instrument is mountcdon a switchboard,and showing the casing of tl c instrument in section with parts of the instrument broken away and other parts in section; Fig. 2 isa detail view of. the marking element Fig. 3 is 'a plan View of the instrument as it is mounted on a switchboard, with arts of the rec'ordingdruni broken awayto s 10w details of construction; Fi 4 is an enlarged. view 1 taken similarly to ig. 3 showing certain details; Fig. 5 is a. view taken at right angles to Fig. 4; and Fig. dis a partial sectional elevation taken on the line 6 6 of Fig. 3.

The instrument as a whole is supported upon avertical base 1 and is surrounded by a suitable casing which may be of glass. A frame or bracket 2 extending from the base carries that portion of the instrument that is designed to measure the variations bf the variable quantity.

In the articular embodiment-of my inventionz-whic I have illustrated in the drawings,

the instrument is designed to record the voltages existing between points in an electric circuit. The measuring mechanism consists of a pair of fixed coils-3 and 4 and a pair of movable coils 5 and 6 angularly displaced with reference to the first-mentioned coils. The fixed coils are secured to across-bar 7 of the frame 2. The coils 3 and 4 as well as the coils 5 and 6 are substantially rectangular. The coils 5 and 6 are larger than the coils 3 and 4 which they .embrace.

The movable coils are secured to a vertical tubularshaft 8.

The coils 5 and 6 which are located'one on each side of the shaft 8, as are the coils 3 and 4, are-separated by space blocks 9 and 10 which maybe made of brass. Clamps 11 and v12 are employed for clamping together thecoils 5 and 6 and the blocks 9 and 10 respectively. The blocks 9 and 10 are apertured -to receive the hollow shaft 8.

Centrally apertured plugs or blocks 13 are placed ineach end of the tube 8.' A fine wire 14 such as a piano wire slightly smaller than the apertures'in the lugs 13 passes lengthwise through the sha t8 and forms a means for positioning the shaft and thereby the movable coils. The. ends of this wire pass through 0 'enings in the frame 2 and are secured to p u s 17 carried by lates 1.8 which are held in p ace against the rame 2. Disks 15 and 16 carried on the inner sidesof the upper ends of the frame 2 are rovided'with centrally located apertures t rough which the wire passes, assist in positioning the wire,

The aperture in the disk 15 passes throughfa central boss 15 extending from the lower face of the disk 15 for some distance. The weight of the movable element offthe meter is sustained by a pair of threads oi -wires 19 which extend from the ufppler side .of the I block 9, one on each sldeo t e shaft 8 to an apert'm'ed disk 20, thus formin a bifilar susension. The lower'end of t e boss 15 is eveled and fits into the aperture in the disk 20 so that the end of the boss is immediately above the end of the hollow-tube 8.. The a erture in the'disk 20 is large enough so that t 1e beveled-end of the boss 15 does not'bear against the walls of the a' ert'ure. .Thedisk 20 is supported from the isk 15 by apair of diametrically o posed flexible membersjfl. The plane in wl iich the flexible members 21 are located is perpendicular to the plane con-.

taining the wiresor threads This construction forms a very desirable means of supporting the weight of the movable element of the meter, as the flexible members 21 with the disk 20 correctly distribute the weights carried by the two filaments 19 and form an e ualizer which obviates thencessity of making the filaments 19'exactly the Same length. v

' Studs 22 in line with the shaft 8 and carried by brackets '23 secured to the outside of the frame 2 each have connected to'them one end of one of a pair of spiral springs 24'. The other ends of these springs are secured to arms 25 which-extend parallel to the shaft 8 and are in turn carried by a pair of arms26. The arms 26 are carried by and extend perpendicularly from the shaft 8 and carry at their outerends a pair of jewel screws 27 in which a shaft 28 parallel to the shaft 8 is pivotally mounted. A tie-bar 29 connects the arms 26 intermediate their ends. A helical spring 30 wound aroundthe shaft 28 and having one erhi sedured to the shaft and, the other end 31 elongated to bear against the tie-bar 29, tends to rotate the shaft'28 in one direction. A short arm 32 carried by the shaft 28 engages with a spring stop 33carried by the tie-bar and prevents the shaft 28 from being rotated against the action of the spring more than a predetermined amount. .The spring stop 33 is provided with a bend '33 and when the shaft 28 is rotated to bring the end of the arm 32 past this bend, the resiliency of thespring 33 is sufficient to hold the arm 32 and shaft 23 in the positionwhich it has assumed against the action of the spring 30. I

An arm 34 extendingv perpendicularly from the shaft 23 near its middle portion suitable marking.

carries at its outer end a device. Th s marking device may be an receptacle,-'-pencii or'the like- .Weights 26 arecarried by arms extending perpen diculariy from the opposite side of the shaft 8 from which the arms 26. extend-.12 These weights. counterbalance .theweightzof the. arms 26 and mechanism. carried thereby. The record surfa cawith whichthe marking; device 35 is; held in engagement-by the. spring 30, consists of-a. strip of; paperwound upon a drum 36. .fThe drum- 36ds carried by a revolving shaft 37 placedper "endicularly to the shaft 8 and supporte in any suitable mannerv from the base :1. A suitable m'echanism'38, whichm'ay-be a spring motor, rotates the drum at a uniform speed in the direction of the arrow shown in Fig.

3. The drum 36 consists of a rim 36 which. may lee-formed of sheet metal, and a pair of.-

one or. spider portions 43and i-3Q Theends ofthe rim portion 36 are turned up-to form outwardly extending flanges-which; assist in positioning-the record strip. The outer edges of the disks or SPl'l EIS may be turned over as, clearly shown in Fig. to

form cylindrical portions which abut against the inner side of the rim portion.

and drum portion may be secured together in any deslrable manner. The spider 43 is near the right-hand side of the drum as viewed in Fig. 3 and the spider 43 is laced about midway of the drum. The spi ers 43 and 43 turn loosely upon the shaft 39. The shaft 39 to the left of the spider 43 as viewed in Fig. 3 is enlarged to form ashoulder against which the disk 43 abuts. The

vent a longitudinal movement of the drum along the shaft toward the left as viewed in Fig. 3. The shaft 39 which is in alinement with and may be an extension of the driving shaft of the spring motor has its outer end journaled in a bearing carried by the crossbar 7 of the frame 2. It has not been thought necessary to illustrate the construction of this bearing. The shaft 39 extends perpendicularly to the shaft 8 but is located somewhat nearer to the base 1. The construcextend into the drum for a considerable disn'phery of the drum thus overhangs the coils. This nesting of the coils within the drum adds largely to the compactness'of the instrument and is a desirable feature. Suitable clips 36" are carried at the periphery of the drum by means of which the record strip may be secured in position.

A collar 40 secured to the shaft 39 has ex-' tending from it perpendicularly to the shaft a pluralityof flexible arms 41. These arms. are turned over at their outer ends and are secured to a" disk 42 as is clearly shown in Fig. 3. The disk 42 is formed with a central aperture through which the shaft- 39 .passes. The resiliency of the arms 41 causes the disk 42 to be pressed so firmly against a disk 43 forming part of the drum 36 that a rotation of the shaft 39 will normally cause a rotation of the drum but not so firmly but that the drum may be set at any desired initial position. 3 The :mechanism for driving the drum may be constructed to cause the drum to make one complete revolution in every twelve hours, twenty-four hours, or other desired interval of time. In such cases it maybe desirable to construct stops which will automatically engage the drum and prevent its further rotation whenever one'comple'te revo lution has beenmade. In Fig. 3 I have shown stops 44 and 45 carried'by the drum and the base 1 respectively, capable of producing. this result. I

I A stud 46 projecting from the disk 43has secured at 'itsou'ter end one end of a spiral spr ng 47. The other end of the spiral l-spring s secured to a fixed support 48 projecting from the framework of the spring l motor 38. The spring 4-7 tends to prevent The disks shoulder and the disk thus cooperate to pretion of the drum is such that the coils can Y tance as-clearly shown in Fig. 3. The pea rotation of the drum in the direction of the arrow shownin Fig. 3, thus 0 posin the action of the spring motor and act a ways to take up th. back lash'of the gearing which driyesthe drum.

As I have before stated, the particular in;- strument illustrated is a volt-meter, the coils 3, 4, 5 and -6 being all arranged in series. Binding posts 49 and 50 carried by the base 1 form the terminals of the meter. Flexible conductors 51, 52 carried by the shaft 8 are in electrical contact with supplemental binding posts or terminals 53 and 54 mounted on the-cross-bar 7 of the frame 2. I have not then ht it necessary to illustrate the exact detai s of the arrangement of the conductors connecting the coils since these arrangements form no part of my present invention.

While I have described the instrument as arranged to operate as a volt-meter, it will be entirely obvious to one skilled in the art that the articular instrument which I have describe might be constructed to operate either as an ammeter, wattmeter, or the like. It will also be apparent that many of the features of novelty disclosed in this case are not limited to their use in connection with electrical measuring instruments but are useful in other relations.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. In an electrical instrument, the combination with a movable coil of stretched wire passed near its fixed or stationary ends through bearin s on the body of the coil, means for supplying electrical current to the coil.

2. In a measuring instrument, the combi nation with a movable element, of a stretched wire on which said element is loosely strung and thereby positioned, and a flexible suspension for sustaining the weight of said element.

3. In a measuring instrument, the.combi nation with a movable element, of a stretched wire on which said element is loosely strung and thereby positioned, and two flexible lilaments connected to saidelement on opposite sides of said wire to sustain the weight of said element.

4. In a measuring instrument, the combination with a rotatable element and abearing .on said element in alinement with the axis of rotation thereof, of a stretched wire smaller than said bearing strung loosely through said bearing to position said elevment, and a bifllar suspension for sustaining,

the weight of said element.

5; In a measuring instrument, the combination with a movable coil of a stretched wire passed axially through said. coil and through hearings on the body of the coil near the fixed ends of said wire, said coil being mounted to slide freely on said wire, and a flexible suspension for sustaining the weight of said coil.

-6. In a measurm-minstrument, the combination with a movable element, of an equalizing member, two flexible supports forsaid member, and two flexible filaments connected to said member and to said element in a lane at right angles to the plane of said flexi le supports.

7. In combination, a shaft, a support, a pair of flexible members depending from said support an equalizing member sustained by said flexible members, a pan of flexible filaments, each of said filaments being connected at oneend to said equalizing member and at the other end to said shaft, the axis of'the shaft passing midway between the flexible filaments and the flexible members, and the flexible filaments being displaced angularly with respect to the flexible members.

8. In combination, asupporting member, a member to be supported, a 'air of flexible members depending from the supporting member and connected at theinlower ends to an equalizer, flexible wires or filaments each connected at one end to the equalizer and at the'oth'er end to the member to be supported, the flexible members and the filaments or wires being angularly dispcsed with respect to one an other.

9. In combination, a support, an equalizing member, flexible members extending from saidsuppcrt to said e ualizing me1nber, flexible wires secured seen at one end'to the equalizing member angularly disposed with reference to the plane in which the flexi- -ble members are located, a tubular shaft to which the other ends of the wires extending from the equalizing member are attached, a wire axially placed iii the tubular shaft and passing throughan aperture in the equalizing member, and a bo'ss extendin from the suuporting member to which t e axially disposed wire in the tube passes, the boss being extended to a pcsition adjacent the end of the shaft. In'witness whereof, I have hereunto set my hand this eighth da of August ,1907.

WIL 1AM H. PRATT. Witnesses: l

' Jonn A-. MCMANUS, J12, Pmmr F. HARRINGTON. 

